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By adding VMA at a dosage of 0 05 cement content the Marsh cone flow rate of WHITE ECC mortar was increased to 28 s corresponding to a fiber dispersion coefficient of around 0 8 Fig 12b As shown in Fig 13 b this method greatly improved the average tensile strain capacity of WHITE ECC from 2 to 3 and reduced the variation in tensile

In this article laboratory and analytical studies of the chloride migration coefficient D are presented The result of studies on chloride migration of Self Compacting Concrete SCC are compared with the corresponding properties of normal concrete with the same water cement ratio w/c and air content Both 28 and 90 days age applied at the start of the testing Six SCC were studied and 2

Classical elastic wave features like pulse velocity and attenuation have been used for decades for concrete condition characterization Relatively recently the effect of frequency has been studied showing no doubt over the dispersive behavior of the material Despite the experimental evidence there is no unified theory to model the material and explain this phase velocity change at

A laboratory scale tracer test has been carried out to improve the characterization of the transport properties of the concrete from the radioactive waste disposal facility at El Cabril Spain High entry pressure was employed in order to perform the experiment in a reasonable time span Lithium bromide and deuterium were used as tracers The conceptual model considered matrix diffusion

ﬁber dispersion decreases with increasing latex/cement Figure 3 Effect of the latex/cement ratio on the void content when the cement paste contains a 0 53 vol carbon ﬁbers and b no ﬁbers 28 Figure 4 Effect of the latex/cement ratio on the measured/calculated conductivity ratio when the cement paste contains 0 53 vol carbon

0 15 B Moderately Unstable 0 15 C Slightly Unstable 0 20 Neutral temperature at 0℃ it could be night or day 0 25 E Slightly Stable night time with radiation inversion and poor dispersion 0 40 F Stable night time with radiation inversion and no dispersion 0 60

where the and are shear viscosity coefficient thermal conductivity coefficient heat capacity at constant pressure and specific heat capacity respectively It is clear from equations and that the absorption attenuation coefficient of stress waves in concrete is directly proportional to the square of the stress wave frequency pared with equation the number of undetermined parameters in

W/C 0 51 0 50 0 54 68 69 It must be added here that all the specimens used in this project were prepared on the two sites by the site workers simultaneously to the 70 fabrication of the slabs and supports of the construction sites A1 and A2 respectively In the authors mind the concrete

At the same time the micro inertia h shows a similar behavior see Fig 2 b climbing from 1 to 2 4 mm and finally to 16 mm for the case of concrete Unlike Ref 12 12 S N Iliopoulos D G Aggelis and D Polyzos Wave dispersion in fresh and hardened concrete through the

4 2 Thermal Conductivity and Specific Heat As shown in Fig 4 2‐1 the specific heat of polycarbonate changes with temperature but it can be considered that this is 1 09 1 17J g k 0 26 0 28cal/g ℃ for the practical temperature range This value does not differ very much from the common synthetic resins and corresponds to about 3 times of iron and

Tables 1 through 8 list concrete masonry wall weights for 4 to 16 inch 102 to 406 mm thick single wythe walls Wall weights for grouted 4 in 102 mm concrete masonry walls are not provided Because of the small core size and resulting difﬁculty in consolidating grout these units are rarely grouted

A laboratory scale tracer test has been carried out to improve the characterization of the transport properties of the concrete from the radioactive waste disposal facility at El Cabril Spain High entry pressure was employed in order to perform the experiment in a reasonable time span Lithium bromide and deuterium were used as tracers The conceptual model considered matrix diffusion

The dispersion coefficient β of PV A fibers in cement mortar was obtained by the following equations Table 1 Dispers ion coefficient of PVA fiber s in cement mortar

The dispersion coefficient β of PV A fibers in cement mortar was obtained by the following equations Table 1 Dispers ion coefficient of PVA fiber s in cement mortar

In reinforced concrete RC structures the compressive strength of concrete can play a crucial role in seismic performance and is usually difficult to estimate Major seismic codes prescribe that concrete strength must be determined essentially from in situ and laboratory tests Mean values obtained from such tests are the reference design values when assessing existing structures under

Separate relationships relating the mix parameters such as w/c ratio and age with mean distribution radius r 0 5 and coefficient d representing dispersion of pores are developed for OPC sand mortars

Coefficient of Standard Deviation The standard deviation is the absolute measure of dispersion Its relative measure is called the standard coefficient of dispersion or coefficient of standard deviati

At the same time the micro inertia h shows a similar behavior see Fig 2 b climbing from 1 to 2 4 mm and finally to 16 mm for the case of concrete Unlike Ref 12 12 S N Iliopoulos D G Aggelis and D Polyzos Wave dispersion in fresh and hardened concrete through the prism of gradient elasticity Int J Solids Struct

Table 2 shows the proportions of CFRC as to validate the FM SEM and ERM methods The additions were dissolved in water and carbon fibers were added and stirred by hand for about 2 min Then this mixture and cement were mixed in a cement mixer for 1–8 min and eight pieces of sample were used every time as to investigate the effect of mixing time on fiber dispersion by FM method

The longitudinal dispersion coefficient is an important index for contaminant transports in rivers Investigating it by using an analytical approach is conducive to obtain its expression with physical meanings and wide application ranges However the analytical solutions are extremely complex for subsequent derivations when many influencing factors such as benthic vegetation and surface wind

W/C 0 51 0 50 0 54 68 69 It must be added here that all the specimens used in this project were prepared on the two sites by the site workers simultaneously to the 70 fabrication of the slabs and supports of the construction sites A1 and A2 respectively In the authors mind the concrete specimens are then

The dispersion can be evaluated by variation coefficient of carbon fiber mass In addition Yang et al 22 introduced four methods to evaluate fiber dispersion which were fresh mixture method

f16 711 Lecture 3 Optical fibers Dispersion induced limitations Example bit rate and bandwidth Calculate the bandwidth and length product for an optical fiber with chromatic dispersion coefficient 8pskm 1nm 1 and optical bandwidth for 10km of this kind of fiber and linewidth of 2nm

The time dependent dispersion theories would predict two different values for the dispersion coefficient at such overlapping points a situation to which Taylor Reference Taylor 1959 objected iv Whatever the theory for preasymptotic dispersion is the dispersion coefficient should

The differences among transverse average concentration using the Taylor model with and without dynamic dispersion coefficient and center of mass velocity are significant at early times but indistinguishable when dimensionless time t D approaches 0 5 Furthermore compared to solutes flowing in a 3D circular tube dispersion

The mean frictional force which is caused by the complex interactions of stream flow and riverbed roughness along a stream reach is commonly described in terms of the bed shear stress τ o or an equivalent shear velocity u In a steady uniform flow the force balance between gravitational force and friction leads to a linear relationship between τ o and the product of mean flow depth D

The dispersion can be evaluated by variation coefficient of carbon fiber mass In addition Yang et al 22 introduced four methods to evaluate fiber dispersion which were fresh mixture method

Classical elastic wave features like pulse velocity and attenuation have been used for decades for concrete condition characterization Relatively recently the effect of frequency has been studied showing no doubt over the dispersive behavior of the material Despite the experimental evidence there is no unified theory to model the material and explain this phase velocity change at

The fiber dispersion coefficient of ECO HDCC presents an increasing trend within 60 RAC content and the coefficient decreases within 80–100 RAC content Compared to sand with a maximum size of 1 18 mm the particle sizes of the RCR are smaller 0 3 mm and 0 16 mm

At the same time the micro inertia h shows a similar behavior see Fig 2 b climbing from 1 to 2 4 mm and finally to 16 mm for the case of concrete Unlike Ref 12 12 S N Iliopoulos D G Aggelis and D Polyzos Wave dispersion in fresh and hardened concrete through the prism of gradient elasticity Int J Solids Struct

The evaluation results in a quantitative pattern of the dispersion coefficient within the range from 0 44 to 0 48 The dispersion and electrical resistivity results demonstrate that a well

Cement water carbon fiber sodium carboxymethyl cellulose and tributyl phosphate in mass = 1 0 4 0 02 0 008 0 0016 The mixing sequence is shown in Fig 1 The water in a beaker was heated to the temperature of 60 C for easy dissolve of dispersion agent Sodium carboxymethyl cellulose was added and was stirred for 60 s by hands Carbon fibers were then added and the dispersion agent

The standard fitting equation based on different absorbance values and GNPs concentrations were shown in inset curves and parameter E was absorption coefficient which represented dispersion effect of dispersants and value of E were 7 573 6 670 5 067 and 4 958 of dispersion with 0 7 g l −1 CO890 0 4 g l −1 CTAB 0 5 g l −1 PVP and 1 0

In this article laboratory and analytical studies of the chloride migration coefficient D are presented The result of studies on chloride migration of Self Compacting Concrete SCC are compared with the corresponding properties of normal concrete with the same water cement ratio w/c and air content Both 28 and 90 days age applied at the start of the testing Six SCC were studied and 2

The evaluation results in a quantitative pattern of the dispersion coefficient within the range from 0 44 to 0 48 The dispersion and electrical resistivity results demonstrate that a well

Coefficient of Standard Deviation The standard deviation is the absolute measure of dispersion Its relative measure is called the standard coefficient of dispersion or coefficient of standard deviati